MIAMI, FL, USA - Sony Open Tennis semifinal action will see Serena Williams square off with Maria Sharapova for the 18th time and Li Na take on soon-to-be Top 10 player Dominika Cibulkova.
Read more details and stats about Thursday's match-ups in our Match Notes.
 Serena Williams (USA #1) vs.  Maria Sharapova (RUS #7)
Head-to-head: Williams leads 15-2
Maria Sharapova often brings out the best in rival and fellow superstar Serena Williams, as after losing two of the first three in their series, the World No.1 has won 14 in a row during a 10 year stretch. But several of their recent contests have been competitive, including a three-setter in last year's Miami final, where Williams improved to 3-0 in their Sony Open Tennis encounters.
"I try to play the best I can against everyone I play. It doesn't matter who I play," Williams said of her terrific record against Sharapova. "I just give my best on that day, and if I win, I win, and if not, then I try again."
After a couple of early challenges this fortnight, six-time Miami champion Williams appeared in championship form in the last two matches, especially in her quarterfinal rout of World No.9 Angelique Kerber. Sharapova has been tested throughout this event, but also had her most impressive showing in the quarterfinals in beating World No.8 Petra Kvitova in straight sets. She has now won 19 of her last 22 matches here and if she can upend Williams, she will be into the Miami final for the fourth straight year and the sixth time overall.
"It's just nice to feel like you're part of a home crowd with so many friends watching and supporting me," Sharapova said. "I spent so many years training in Florida and I think because I played so long in these conditions, in the humidity, knowing storms can come in any minute, you adjust to that and understand what goes on. I've had nice success but obviously there's a couple more matches to go."
 Li Na (CHN #2) vs.  Dominika Cibulkova (SVK #11)
Head-to-head: Li leads 6-0
Though Dominika Cibulkova has had a forgettable history against Li Na, perhaps the confidence she has gained from ensuring a rise to the Top 10 will make a difference. And while she has lost all six encounters in their series, including this year in the Australian Open final and Indian Wells quarterfinals, Cibulkova did extend Li to a third set in their clash two weeks ago. She is coming off two dramatic victories, a three-setter over Venus Williams in the fourth round and another over Agnieszka Radwanska in the quarterfinals that saw her overcome three match points in the second set en route to her 13th Top 5 win.
Tied with Cibulkova for most wins on the WTA this season is Li, whose 20th was a quarterfinal defeat of Caroline Wozniacki on Wednesday in which she was tested but did not surrender a set just like the rest of her matches this fortnight.
Li is the Sony Open Tennis' first Chinese semifinalist and Cibulkova is Slovakia's second after Karina Habsudova in 1996.
Find the listings for Thursday's play on the WTA TV developed by Xerox.